Power controller

ABSTRACT

A command transmission/reception section ( 4 R), a power-control determination section ( 8 ) and a power control section ( 9 ) are provided in a controlled device ( 3 ) which is connected to a network ( 1 ) and which performs power control in response to a command transmitted from a control device ( 2 ). Upon receipt of a power control command from the control device ( 2 ), the power-control determination section ( 8 ) determines as to power-on/power-off in units of a block, and performs power control on the basis of a result of the determination. Consequently, unnecessary power-on in, for example, video reservation can be prevented.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a power controller for executinginternal power-on/power-off in response to a power control commandreceived from another device in an audio/video device connected via adigital network according to IEEE 1394 or the like.

2. Discussion of the Related Art

In most cases of conventional televisions (hereinafter, referred to as“TV”) or the like, a power operation is performed from the outside of aTV main body; that is, power-on of a TV main body is performed by usinga remote controller. The TV main body is powered on when a power-oncommand is received via a remote control signal in a standby state.Power-on is performed apparently in the presence of a user in thevicinity of the TV.

For the IEEE 1394 network, control commands of audio/video devices arestandardized by an industrial standardization association. Mounting of adevice-control-command processing program according to the standardsenables the operation of audio/video devices including a TV, DVD playerand VTR via a network. Power control commands (instructions) areprescribed in the standards. Using the commands enables thepower-on/power-off of the device to be performed from an external deviceconnected to the network. In addition, the power source of theaudio/video device can be controlled from a personal computer in whichsoftware for transmitting the power control commands is installed.

In a VTR in which a video record reservation is set, on reachingreserved time, a primary power source is turned on from a standby state,and the power source state of a TV is checked. As a result of thechecking, if the power source is in an off state, a power controlcommand is issued to power on of the TV, and video recording is thenstarted. In this case, if the video recording is reserved for abroadcast, a CRT of the TV need not be activated to illuminate; and itis preferable that only a tuner portion is powered on. However, when theVTR has transmitted a command to power on the overall device of the TV,a monitor portion including the CRT and a video output circuit isunexpectedly driven to operate. Driving the CRT to illuminate in theabsence of the TV user is not preferable for the TV. This also producesdisadvantages not only in safety but also in power saving.

Generally, while an audio/video device is configured of a plurality offunctional blocks, functional blocks for performing power-on with apower control command are specified depending on controlled devices. Assuch, unnecessary power-on can take place for functional blocks whichare unwanted to power on when, for example, a user is not in presence,and for either a TV display portion or monitor portion not viewed by auser.

SUMMARY OF THE INVENTION

The present invention is proposed in view of the conventional problemsdescribed above, and an object thereof is to enable a power controlcommand to be discretely outputted for a functional block from onedevice (referred to as “control device”) to another device (referred toas “controlled device”) among a plurality of devices connected via anetwork. Another object of the present invention is to realize a powercontroller which enables power-on/power-off to be performedcorresponding to, for example, the type and the operational state of thecontrolled device, so that power saving can be implemented.

A power controller of the present invention is a power controller forperforming power control of an own local device including at least onefunctional block in accordance with a power control command transmittedfrom an external device connected to a network, the power controllerincluding: a command transmitting/receiving section which receives thepower control command from the external device and which transmits aresponse of the own local device; a power control section which performspower-on/power-off of the own local device at least in units of a block;and a power-control determination section which performs a determinationas to power-on/power-off of each block on the basis of a power controlcommand supplied via the command transmitting/receiving section andwhich outputs a result of the determination to the power controlsection.

In addition, a power controller according to the present inventionfurther includes: a determination-information recording section which,in units of a functional block of the own local device, preliminarilystores determination information used to perform a determination as towhether to validate or invalidate a power control command transmittedfrom the external device, wherein the power-control determinationsection performs a determination as to whether to validate or invalidateexecution of the power control command on the basis of information inthe determination-information recording section upon receipt of thepower control command from the external device, performs a determinationas to individual-block power-on/power-off only for a valid block on thebasis of the power control command, and outputs a result of thedetermination to the power control section.

Further, a power controller according to the present invention, furtherincludes: a determination-information recording section whichpreliminarily stores determination information used to perform adetermination as to whether to validate or invalidate a power controlcommand transmitted from the external device, in units of the functionalblock of the own local device; and an external-device identifyingsection which identifies at least one of a type and a function of theexternal device connected to the network, wherein upon receipt of thepower control command from the external device, the power-controldetermination section performs a determination as to whether to validateor invalidate execution of the power control command on the basis ofinformation in the determination-information recording section,identifies whether or not the device has involved an operation from auser in accordance with information of at least one of the type and thefunction which has been identified by the external-device identifyingsection, outputs the power control command received from the outside tothe power control section when having determined the device to haveinvolved an operation performed from the user, and outputs a powercontrol signal received from the outside to the power control section onthe basis of a result of the determination in the other case.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system configuration view showing a system in which aplurality of audio/video devices is connected to a network.

FIG. 2 is a system configuration view of a controlled device, and acontrol device including a power controller according to embodiment 1 ofthe present invention.

FIG. 3 is a system configuration view of a controlled device, and acontrol device including a power controller in embodiment 2 of thepresent invention.

FIG. 4 is an explanatory view showing information preserved in aninformation recording section in the power controller in embodiment 2.

FIG. 5 is a flowchart showing an example procedure of power-on inaccordance with determination information in the power controlleraccording to embodiment 2.

FIG. 6 is a system configuration view of a controlled device and acontrol device including a power controller in embodiment 3 of thepresent invention.

FIG. 7 is an explanatory view showing information preserved in anexternal-device identifying section in the power controller according toembodiment 3.

FIG. 8 is a flowchart showing an example procedure for performingpower-on in the power controller according to embodiment 3.

FIG. 9 is an explanatory view showing an example state of a connectiondestination device in the power controller according to embodiment 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows an example in which a plurality of audio/video devicesconnected to a network (bus connection network) 1. In this case, a VTR,TV, VCR, DVC and PC are assumed to be connected to the network 1. Wheneach of these devices operates as one of these modes; namely it operatesas a control device 2, as a controlled device 3 or as a device havingthese both functions. The PC stands for a personal computer and works asa control device 2. The VTR stands for a video tape recorder, the TVstands for a television and includes a tuner section and a monitorsection with a CRT, the VCR stands for a video camera recorder, and theDVC stands for a digital video camera. Each of these devices is assumedto include the two functions of the control device 2 and the controlleddevice 3.

In case an audio/video device has the function of the controlled deviceto perform power control, even when a user is not present for reservedoperation, the controlled device can be powered on with a power-oncommand being transmitted via the network. The overall configuration iscommon to each embodiment. Hereinafter, each of the embodiments will bedescribed.

(Embodiment 1)

FIG. 2 is a block diagram showing basic connection relationships amongindividual devices including a power controller according toembodiment 1. As shown in FIG. 2, at least one pair of a control device2 and a controlled device 3A is connected via a network 1. The pair ofthe control device 2 and the controlled device 3A is, for example, ahome-use audio/video device. While having the same configuration, thecontrolling side is referred to as the control device 2, and thecontrolled side is referred to as the controlled device 3A. The controldevice 2 is assumed to have a function of transmitting control commandsused to operate the other device, and the controlled device 3 is assumedto have a function of executing the transmitted control commands.

The control device 2 is configured to include a commandtransmission/reception (T/R) section 4S and a control section 5. Thecontrol section 5 issues a power-on control command to the controlleddevice 3A, and interprets the contents of a response returned from thecontrolled device 3A. The command transmission/reception section 4Sperforms operations, such as transmission of a control command which hasbeen outputted from the control section 5 via the network 1, andreception of a response which has been outputted from the controlleddevice 3A.

The controlled device 3A is configured to include a commandtransmission/reception section 4R, a command execution section 6, apower control section 9, and blocks of its own. Each of the powercontrollers of the embodiments is assumed to include at least thecommand transmission/reception section 4R, a power-control determinationsection 8, and the power control section 9.

The command execution section 6 receives a control command from thecontrol device 2 via the command transmission/reception section 4R,determines the type of the command, and processes the command. With a TVused for the controlled device 3A, the command execution section 6 isconfigured of blocks of, for example, a channel-selection controldetermination section 7 for selecting a broadcast channel, and apower-control determination section 8 for determining, for example,power-on/power-off. The command execution section described above isdifferent depending on the function of a device.

The power-control determination section 8 determines as to thepower-on/power-off of each of the blocks in response to a power controlcommand fed via the command transmission/reception section 4R, and sendsthe determination result as an output to the power control section 9.The power control section 9 performs power-on/power-off of its own atleast in units of the block. With a TV used for the controlled device3A, a tuner section 11 and a monitor section 12 are additionallyprovided.

Hereinafter, basic operations of the power control in the controlleddevice 3A will be described. The control device 2 commands thecontrolled device 3A to perform, for example, power-on/power-off. Fordetails, the control section 5 generates a power-on command according toa command transmission format, and sends the command to the network 1via the command transmission/reception section 4S.

Subsequently, the controlled device 3A receives a control commandaddressed to itself via the command transmission/reception section 4R,and uses the command execution section 6 to interpret the controlcommand. Upon having determined the command as a power control commandaccording to a command format thereof, the controlled device 3A passesprocessing to the power-control determination section 8. Thepower-control determination section 8 determines that the command is toperform power-on/power-off for which one of the blocks in the controlleddevice 3A. Then, a command (power control command) for performingpower-on/power-off for a corresponding block is outputted to the powercontrol section 9. In this case, since the TV is used for the controlleddevice 3A, the power control section 9 is assumed to control the powersource of the tuner section 11 independently of the power source of themonitor section 12. After the power control section 9 has performed thepower-on/power-off of the predetermined block, the power-controldetermination section 8 generates the result according to a responseformat and then transmits the result to the control device 2 via thecommand transmission/reception section 4R.

In the control device 2, the command transmission/reception section 4Sreceives a response from the controlled device 3A and posts anotification thereof to the control section 5. In this manner, thecontrol device 2 can recognize completion of the power-on/power-off ofthe controlled device 3A. Using the control method enables power controlfor another device to be implemented from a specific device connected tothe network 1. Command formats for, for example, IEEE 1394 powercontrol, are disclosed in detail in the document of “1394 TradeAssociation” entitled “AC/C Digital Interface Command Set GeneralSpecification (Version 3.0)” issued by the industrial standardizationassociation.

(Embodiment 2)

Hereinafter, a power controller according to embodiment 2 of the presentinvention will be described. FIG. 3 is a configuration view showingbasic connection relationships among individual devices including apower controller according to embodiment 2. The same reference numeralsare assigned to the same portions as those in embodiment 1, and thedescription thereof will be omitted. A controlled device 3B isconfigured to include a determination-information recording section 10in addition to the command transmission/reception section 4R, thecommand section 6 including the channel-selection control determinationsection 7 and the power-control determination section 8, and the powercontrol section 9. With a TV used for the controlled device 3B, thetuner section 11 and the monitor section 12 are provided.

The determination-information recording section 10 is formed of anonvolatile memory such as an EEPROM, and preserves flag informationprovided to, for example, enable a command execution or disable thecommand execution upon receipt of a power control command. For example,when a power control command has been issued from an external device,the flag is set to “0” not to execute the command, whereas the flag isset to “1” to enable the command execution. The power-controldetermination section 8 preliminarily reads out the flag informationfrom the determination-information recording section 10. Then, uponreceipt of the power control command from the control device 2, thepower-control determination section 8 determines whether to execute thecommand in accordance with the flag information, and feeds the powercontrol command to the power control section 9.

In addition, it is assumed that when power-on/power-off is individuallyperformed in each block of the controlled device 3B, flag information inunits of each block is set in the determination-information recordingsection 10. For example, as in a TV, blocks as a tuner section 11 forselecting broadcast channels and a monitor section 12 for displayingvideo are individually provided, and power control is performed in unitsof the block. In this case, power-on/power-off of each of the blocks canbe discretely implemented in accordance with the power control commandreceived from the external control device 2.

FIG. 4 shows example flag information which is recorded in thedetermination-information recording section 10 of the presentembodiment. Referring to the figure, numeral 21 denotes blockidentification information, and numeral 22 denotes flag information. Inthe example configuration, the controlled device 3B is a TV in which atuner section has a decoder for a communications satellite or broadcastsatellite. The block identification units are, for example, set as atotal device (UNIT), a tuner section (TUNER) and a monitor section(MONITOR). The flags are assumed to represent validity/invalidity ofpower control for each of the identification units such that theinvalidity is set to “0”, and the validity is set to “1”. The blockidentification information 21 may be set using a unique number foridentification among the devices instead of using the character string.

In the controlled device, when the flag for the device totality (UNIT)is “1” the flag value for each block need not be checked, and processingis set such that power control is accepted for all the blocks. On theother hand, processing is set such that when the flag for devicetotality (UNIT) is “0”, the flag of each of the blocks belonging to aclass lower than it is checked; when the flag is “1”, power control isperformed for the block; and when the flag is “0”, power control is notperformed.

FIG. 5 is a flowchart showing example power-on processing in aconfiguration of using a TV as the controlled device 3B. At step S1,upon receipt of a power-on control command in the controlled device 3Bfrom the control device 2, the command execution section 6 startsinterpretation of the command. Then, at step S2, information is read outof the determination-information recording section 10. Subsequently, ifthe command is identified for the unit power-on, the operation proceedsto step S4, and checks the flag for the unit. If the flag is “1”,processing branches to step S5. When processing has branched to the stepS5, the tuner section 11 and the monitor section 12 are powered on. Atthe aforementioned step S3, if the command is identified not to be aunit power-on command, processing proceeds to step S6 and determineswhether the command is a tuner power-on command. If the command is thetuner power-on command, processing proceeds to step S7, and checks thetuner flag of the recording section 10. At step S4, if the flag for theunit is “0”, processing proceeds to step S8 and checks the flag for thetuner of the recording section 10. At individual steps S7 and S8 if theflag for the tuner is determined as “1”, processing branches to step S9and powers on the tuner. At step S6 if the command is determined not tobe a tuner power-on command, and at step S7 the flag for the tuner isdetermined to be “0”, processing proceeds to step S10 and checks whetherthe command is a monitor power-on command. If the command is the monitorpower-on command, processing proceeds to step S11, and checks whetherthe flag for the monitor of the recording section 10 is “1”. If the flagis “1”, in step S12 the monitor is powered on. If either step S10 or S11determines the command is not a monitor power-on command or the flag forthe monitor is not “1”, processing terminates. While description isprovided regarding the power-on, power-off is assumed to be performed ina similar manner: however, the power-off operations may be carried outaccording to the command.

When external power control is not desired at all, all values of flagsin the determination-information recording section 10 in the controlleddevice 3B may be set to “0”. Generally, these flag values are preset atthe time of initialization setting. However, the setting method may besuch that a function of setting is displayed using an on-screen display(OSD) with, for example, a TV-screen display or a display according to adisplay device such as a LED to enable the values to arbitrarily be setby a user.

The control processing configured as described above enables, forexample, a determination of a device that should not be externallypowered on and a determination as to whether power-on can be performedin units of the functional block. Particularly, the control candiscretely be performed for a block such as a CRT of a TV when no useris in a room. As such, a significant advantage can be obtained in thatthe control contributes to improvement in safety and power saving of aTV, whose power consumption has increased according to an increase inthe size of its CRT.

(Embodiment 3)

Hereinafter, a power controller according to embodiment 3 of the presentinvention will be described. FIG. 6 is a configuration view showingbasic connection relationships among individual devices including apower controller according to the present embodiment. Also in thepresent embodiment, the same reference numerals are assigned to the sameportions as those in the first and second embodiments, and thedescription thereof will be omitted. A controlled device 3C of theembodiment 3 is configured to include an external-device identifyingsection 13 in addition to the command transmission/reception section 4R,the command section 6 including the channel-selection controldetermination section 7 and the power-control determination section 8,the power control section 9, and the determination-information recordingsection 10. With a TV used for the controlled device 3C, the tunersection 11 and the monitor section 12 are provided.

The external-device identifying section 13 checks all controlled devicesconnected to the network 1, that is, audio/video devices, and detectsthe type and the function of each of the devices, thereby creating aninformation table described below. For the audio/video device connectedto the IEEE 1394 network, a command for checking an element constitutingthe device is defined as an essential command.

For example, a SUBUNIT INFO command is used to check functionsconstituting a device. A UNIT INFO command is used to checkrepresentative functions of a device for determining the type thereof.The functions includes a monitor, a disk recorder/player, a taperecorder/player, a tuner, and a camera as constitution elements of theaudio/video device; and a bulletin board (indicated as “BB” in thefigure) called as “resource schedule board” which serves to discloseintradevice reserved information.

FIG. 7 shows an example of the information table showing functionalconfigurations and control states of all the connected devices. Thetable contains an identifier description field 23, a device type field24, and a function constitution description field 25. The informationtable is created using the UNIT INFO command and the SUBUNIT INFOcommand. For example, in many cases, a TV essentially requires a monitorand a tuner, and may be configured to include a reservation function. Inthe case of the TV including the above components, responses to theSUBUNIT INFO command are correspond to the monitor, tuner, and bulletinboard; and a response to the UNIT INFO command corresponds to a monitor,and the type corresponds to a TV. When new devices are connected to thenetwork, the external-device identifying section 13 retrieves detailedinformation of the devices as shown in FIG. 7 by using not only the UNITINFO command and the SUBUNIT INFO command but also standardized commandsfor individual audio/video devices. For example, a TV with theidentifier “003” includes a monitor and a tuner. Also, a TV with theidentifier “004” includes a bulletin board in addition to a tuner and amonitor.

Further, control-condition description fields 26 and 27 are added intothe aforementioned table. Registered in the non-condition controldescription field 26 are devices including a DVC with the identifier“007”, an AMP with the identifier “009”, and a DVD player with theidentifier “010”. In either of the devices with the identifiers “007”and “009”, a device such as a monitor is not provided, in which controlis unnecessary to be performed so as not to feed the power to a part ofthe functional blocks in opposition to control commands. In this case,control commands from the control device 2 are all accepted. On theother hand, registered in the conditional-control description field 27are devices including tuners with the identifiers “001” and “002”, TVswith the identifiers “003” and “004”, and DVHSs with identifiers “005”and “006”, and so on. Control is considered necessary to be performedfor these devices so as not to feed the power to a part of functionalblocks in opposition to control commands. As such, in the controlleddevice, even when a power control command to feed the power of a totaldevice is received, power control is performed according to a ruleregistered in the determination-information recording section 10.

Preferably, identifiers according to Extended Unique Identifier64(EUI64) of IEEE 1394 are used for device-specific identifiers. The typesof the devices in the description field 24 and the functionalconfigurations of the devices in the device-constitution descriptionfield 25 are each shown with a character string for the convenience ofexplanation. However, using SUBUNIT IDs in 1394TA documents enablesgreater memory savings.

The necessity of rechecking of a device once identified can be obviatedby writing the above-described information to the nonvolatile memorysuch as an EEPROM. In the controlled device, when performing deviceidentification of a tape recorder/player by using a device-specificcommand, a digital VHS, a DV, or the like can be identified from a dataformat which can be used by the device according to the use of anoutput-signal mode, a tape record format, and the like.

Hereinafter, operation of the power controller configured as describedwill be described using a flowchart shown in FIG. 8. In the powercontrol determination section 8 of the controlled device 3C shown inFIG. 6, upon receipt of a power-on control command has been receivedfrom a control device 2, the type of the control device 2 is retrievedfrom the external-device identifying section 13. At step T1, the powercontrol section 9 shown in FIG. 6 checks as to whether the controldevice 2, which has transmitted the control command, can be identifiedfor the device type.

At step T1, if the control device 2 is determined identifiable, thedevice type is identified. Then processing proceeds to step T2, andchecks as to whether the functional configuration is identifiable in thestep. This can be determined by referencing the description field 25corresponding to the identifier shown in FIG. 7. At step T2 if thefunctional configuration is determined identifiable, processing proceedsto step T3, and performs checking at the step as to whether the devicehas involved a user operation in accordance with theunconditional-control description field 26 of the table in FIG. 7. Asthe DVC with the identifier “007” or the AMP with the identifier “009”,if the checked device is determined to have involved a user operation,processing proceeds to step T4, and performs power control according tothe control command at the step. Suppose, from the type of the controldevice, the control device 2 is apparently known to operate thecontrolled device 3C through a user operation as the DVC (digital videocamera) with the identifier “007” and the DVD player with the identifier“010” which are shown in FIG. 7. In this case, the power-controldetermination section 8 does not use information retained by thedetermination-information recording section 10. In this instance, thepower-control determination section 8 sends a power control command tothe power control section 9 according to the power control command.Thereby, the user of the control device 2 determines that a person ispresent around the controlled device 3C, and performspower-on/power-off.

At step T3, if the device is determined not to have involved a useroperation, processing proceeds to step T5, and checks thereat as towhether the device includes a video-recording function. This can bedetermined from the contents of the description field 25 shown in FIG.7. If the device is determined not to include a video-recordingfunction, processing proceeds to step T4, and performs power control ofa specified functional block at the step. The power control can beperformed according to the received command without referencing thecontents of the determination-information recording section 10. If thedevice is determined to include a video-recording function, processingproceeds to step T6, and checks the device state thereat.

An example device state is shown in FIG. 9. A user-operation state for aDVHS is one of, for example, playback, fast playback, rewind playback,fast forward, and rewind. Substantially similar to the DVHS, for a DVDplayer as a device, the state is one of playback, fast playback, andrewind playback, although the state is different depending on the devicetype. For a TV as a device, only a monitor power-on is set as theuser-operation state.

At step T6 if the device state is determined to be a user-operation,processing proceeds to step T4; whereas, if the device state isdetermined not to be a user operation, processing proceeds to step T7.At step T7, processing checks as to whether reserved information isretrievable in a video-recording state. If the information is determinedretrievable, processing proceeds to step T8, and if not, processingproceeds to step S9. At step T8 processing checks whether reservation isin process. If reservation is in execution, processing proceeds to stepT9. On the other hand, at step T1 if the device is not identifiable, andat step T2 if the functional configuration is not identifiable,processing proceeds to step T9. At step T9, as in embodiment 2, powercontrol is performed according to the information stored in thedetermination-information recording section 10 shown in FIG. 6 and thecontrol command. If reservation is not in process, processing proceedsto step T4, and performs power control of a specified block in the step.The above operations enable the power control to be implemented inconformance to the type, function, and use state of the external device.

In the present embodiment, the power is controlled according toinformation stored in the determination-information recording section 10at step T9. However, in order to secure safety, the configuration may besuch that not all the power-on commands are executed for a device nothaving the determination-information recording section 10 when step T9is reached.

It is to be understood that the present invention is not limited to anyone of the embodiments, and various modifications and corrections may beimparted thereto within the scope of the claims of the invention.

As described above, according to the present invention, power controlfrom an external device connected to a network can be implementedthrough determination made in accordance with setting information of anown local device and the function of a partner device. Particularly, foran audio/video device, power-on control can be implemented on the basisof the total device and in units of a functional block. Thereby, thepower can be operated from the external device in consideration ofsafety and power saving.

INDUSTRIAL APPLICABILITY

According to the present invention, among a plurality of devicesconnected via a network, a power control command can be outputted inunits of a functional block from one device (referred to as “controldevice”) to another device (referred to as “controlled device”). Inaddition, a power controller can be realized that enablespower-on/power-off to be implemented so as to achieve power savingcorresponding to, for example, the type and the operation state of thecontrolled device.

1. A power controller for use in a local device having a plurality offunctional blocks and that is connected to a bus connection network, thepower controller performing power control in accordance with a powercontrol command transmitted from an external device connected to the busconnection network, the power controller comprising: a commandtransmitting/receiving section which receives the power control commandfrom the external device and which transmits a response from the localdevice; a power control section which independently performspower-on/power-off of one of the functional blocks of the local device;and a power-control determination section which performs a determinationas to power-on/power-off of the functional blocks on the basis of apower control command supplied via said command transmitting/receivingsection and which outputs a result of the determination for each of thefunctional blocks to said power control section.
 2. The power controlleraccording to claim 1, further comprising: a determination-informationrecording section which preliminarily stores determination informationof each of the functional blocks of the local device used to perform adetermination as to whether to validate or invalidate a power controlcommand transmitted from the external device, wherein said power-controldetermination section performs a determination as to whether to validateor invalidate execution of said power control command on the basis ofinformation in said determination-information recording section uponreceipt of the power control command from the external device, performsa determination as to individual block power-on/power-off only for avalid block on the basis of the power control command, and outputs aresult of the determination to said power control section.
 3. The powercontroller according to claim 2, wherein said determination-informationrecording section includes a flag which performs a determination as towhether to validate each of the functional blocks of the local deviceand a flag for performing a determination as to whether to validate orinvalidate a control command in each of the functional blocks.
 4. Thepower controller according to claim 1, further comprising: adetermination-information recording section which preliminarily storesdetermination information of each of the functional blocks of the localdevice used to perform a determination as to whether to validate orinvalidate a power control command transmitted from the external device;and an external-device identifying section which identifies at least oneof a type and a function of the external device connected to the busconnection network, wherein upon receipt of the power control commandfrom the external device, in accordance with information of at least oneof a type and a function of the external device identified by theexternal-device identifying section, said power-control determinationsection outputs the externally inputted power control command to saidpower control section as a valid command when the device has beendetermined to be able to permit an operation, determines the powercontrol to each of the functional blocks corresponding to the powercontrol command from the external device, and outputs a result of thedecision to said power control section wherein the power control commandis invalid on the basis of determination information received from saiddetermination-information recording section when the device has beendetermined to be unable to permit an operation.
 5. The power controlleraccording to claim 4, wherein said external-device identifying sectiongenerates, an information table of each external device connected to thebus connection network, the information table has an area which stores atype and a function thereof, and a conditional-control area used toperform a determination as to whether or not to perform conditionalcontrol based on determination information in saiddetermination-information recording section in response to a powercontrol command inputted from the each external device.
 6. The powercontroller according to claim 1, further comprising: adetermination-information recording section which preliminarily storesdetermination information of the functional blocks of the local deviceused to perform a determination as to whether to validate or invalidatea power control command transmitted from the external device; and anexternal-device identifying section which identifies at least one of atype and a function of the external device connected to the busconnection network, wherein upon receipt of the power control commandfrom the external device, in accordance with information of at least oneof a type and a function of the external device identified by saidexternal-device identifying section, said power-control determinationsection outputs the externally inputted power control command to saidpower control section as a valid command when the device has beendetermined to be able to permit operation and has been determined to bein a user-operated state, and outputs determination information of eachof the functional blocks corresponding to the power control command fromthe external device to said power control section, when the powercontrol command is invalid, on the basis of determination informationreceived from said determination-information recording section when thedevice has been determined to be unable to permit an operation and hasbeen determined not to be in a user-operated state.
 7. The powercontroller according to claim 6, wherein said external-deviceidentifying section generates an information table of each externaldevice connected to the bus connection network, the information tablehas an area which stores a type and a function thereof, and aconditional-control area used to perform a determination as to whetheror not to perform conditional control based on determination informationin said determination-information recording section in response to apower control command inputted from the each external device.
 8. Thepower controller according to claim 1, further comprising: adetermination-information recording section which preliminarily storesdetermination information of the functional blocks of the local deviceused to perform a determination as to whether to validate or invalidatea power control command transmitted from the external device; and anexternal-device identifying section which identifies at least one of atype and a function of the external device connected to the busconnection network, wherein upon receipt of the power control commandfrom the external device, in accordance with information of at least oneof a type and a function of the external device identified by theexternal-device identifying section, said power-control determinationsection outputs the externally inputted power control command to saidpower control section as a valid command when the device has beendetermined to be able to permit an operation, has been determined to bein a user-operated state, and has been determined to be areservation-recording state, and outputs determination information ofeach the functional blocks corresponding to the power control commandfrom the external device to said power control section, in the case thepower control command is invalid, on the basis of determinationinformation received from said determination-information recordingsection when the device has been determined to be unable to permit anoperation, has been determined not to be in a user-operated state, orhas been determined not to be in a reservation-recording state.
 9. Thepower controller according to claim 8, wherein said external-deviceidentifying section generates an information table of each externaldevice connected to the bus connection network, the information tablehas an area which stores a type and a function thereof, and aconditional-control area used to perform a determination as to whetheror not to perform conditional control based on determination informationin said determination-information recording section in response to apower control command inputted from the each external device.
 10. Asystem for performing power control comprising: an external devicehaving a control section for issuing a power control command; a localdevice having a plurality of functional blocks and a power controllerfor performing power control of each of the functional blocks; a busconnection network connecting the external device and the local device;wherein the power controller comprises a command transmitting/receivingsection which receives the power control command from the externaldevice and which transmits a response from the local device; a powercontrol section which independently performs power-on/power-off of oneof the function blocks of the local device; and a power-controldetermination section which performs a determination as topoweron/power-off of the functional blocks on the basis of a powercontrol command supplied via said command transmitting/receiving sectionand which outputs a result of the determination for the functionalblocks to said power control section.
 11. The system for performingpower control according to claim 10, wherein the power controllerfurther comprises a determination-information recording section whichpreliminarily stores determination information of each of the functionalblocks of the local device used to perform a determination as to whetherto validate or invalidate a power control command transmitted from theexternal device, wherein said power-control determination sectionperforms a determination as to whether to validate or invalidateexecution of the power control command on the basis of information insaid determination-information recording section upon receipt of thepower control command from the external device, performs a determinationas to individual block power-on/power-off only for a valid block on thebasis of the power control command, and outputs a result of thedetermination to said power control section.
 12. The system forperforming power control according to claim 11, wherein saiddetermination-information recording section includes a flag whichperforms a determination as to whether to validate each of thefunctional blocks of the local device and a flag for performing adetermination as to whether to validate or invalidate a control commandin each of the functional blocks.
 13. The system for performing powercontrol according to claim 10, wherein the power controller furthercomprises a determination-information recording section whichpreliminarily stores determination information of each of the functionalblocks of the local device used to perform a determination as to whetherto validate or invalidate a power control command transmitted from theexternal device; and an external-device identifying section whichidentifies at least one of a type and a function of the external deviceconnected to the bus connection network, wherein upon receipt of thepower control command from the external device, in accordance withinformation of at least one of a type and a function of the externaldevice identified by the external-device identifying section, saidpower-control determination section outputs the externally inputtedpower control command to said power control section as a valid commandwhen the device has been determined to be able to permit an operation,determines the power control to each of the functional blockscorresponding to the power control command from the external device, andoutputs a result of the decision to said power control section whereinthe power control command is invalid on the basis of determinationinformation received from said determination-information recordingsection when the device has been determined to be unable to permit anoperation.
 14. The system for performing a power control powercontroller according to claim 13, wherein said external-deviceidentifying section generates an information table of each externaldevice connected to the bus connection network, the information tablehas an area which stores a type and a function thereof, and aconditional-control area used to perform a determination as to whetheror not to perform conditional control based on determination informationin said determination-information recording section in response to apower control command inputted from the each external device.
 15. Thesystem for performing a power control according to claim 10, whereinsaid power controller further comprises a determination-informationrecording section which preliminarily stores determination informationof the functional blocks of the local device used to perform adetermination as to whether to validate or invalidate a power controlcommand transmitted from the external device; and an external-deviceidentifying section which identifies at least one of a type and afunction of the external device connected to the bus connection network,wherein upon receipt of the power control command from the externaldevice, in accordance with information of at least one of a type and afunction of the external device identified by said external-deviceidentifying section, said power-control determination section outputsthe externally inputted power control command to said power controlsection as a valid command when the device has been determined to beable to permit and operation and has been determined to be in auser-operated state, and outputs determination information of each ofthe functional blocks corresponding to the power control command fromthe external device to said power control section, when the powercontrol command is invalid, on the basis of determination informationreceived from said determination-information recording section when thedevice has been determined to be unable to permit an operation and hasbeen determined not to be in a user-operated state.
 16. The system forperforming a power control according to claim 15, wherein saidexternal-device identifying section generates an information table ofeach of the external device connected to the bus connection network, theinformation table has an area which stores a type and a functionthereof, and a conditional-control area used to perform a determinationas to whether or not to perform conditional control based ondetermination information in said determination-information recordingsection.
 17. A system for performing a power control according to claim10, wherein the power controller further comprises adetermination-information recording section which preliminarily storesdetermination information of the functional blocks of the local deviceused to perform a determination as to whether to validate or invalidatea power control command transmitted from the external device; and anexternal-device identifying section which identifies at least one of atype and a function of the external device connected to the busconnection network, wherein upon receipt of the power control commandfrom the external device, in accordance with information of at least oneof a type and a function of the external device identified by saidexternal-device identifying section, said power-control determinationsection outputs the externally inputted power control command to saidpower control section as a valid command when the device has beendetermined to be able to permit an operation, has been determined to bein a user-operated state, and has been determined to be areservation-recording state, and outputs determination information ofeach of the functional blocks corresponding to the power control commandfrom the external device to said power control section, when the powercontrol command is invalid, on the basis of determination informationreceived from said determination-information recording section when thedevice has been determined to be unable to permit an operation, has beendetermined not to be in a user-operated state, or has been determinednot to be in a reservation-recording state.
 18. The system forperforming a power control according to claim 17, wherein saidexternal-device identifying section generates an information table ofeach of the external device connected to the bus connection network, theinformation table has an area which stores a type and a functionthereof, and a conditional-control area used to perform a determinationas to whether or not to perform conditional control based ondetermination information in said determination-information recordingsection.